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A210890 Dates after Jan 01 00 in chronological order which are palindromic when they are written in the format D.M.YY. The terms are listed as numbers (without the dots). 4

%I

%S 10101,10201,10301,10401,10501,10601,10701,10801,10901,101101,20102,

%T 20202,20302,20402,20502,20602,20702,20802,20902,201102,30103,30303,

%U 30403,30503,30603,30703,30803,30903,301103,1111,11111,11211,11311,11411,11511,11611,11711

%N Dates after Jan 01 00 in chronological order which are palindromic when they are written in the format D.M.YY. The terms are listed as numbers (without the dots).

%C There are exactly 322 such palindromic dates between Mar 1 00 and Dec 31 99 (see b-file for the complete list).

%C See A210889 for the number of days after 'Mar 1 00' to get such a palindromic date.

%C The definition is different from A210892 in that the dates are considered as numbers.

%C Some numbers occur twice since the dates are not unique without the dots. For example, the number 11211 may represent the date 11.2.11 (Feb 11 11) or 1.12.11 (Dec 1 11). The complete list of such dates is 11.1.11, 11.2.11, 1.11.11, 1.12.11, 21.1.12, 21.2.12, 2.11.12, 2.12.12, 31.1.13 and 3.11.13 which correspond to the terms with n=31,32,41,43,45,46,55,57,59 and 65.

%H Hieronymus Fischer, <a href="/A210890/b210890.txt">Table of n, a(n) for n = 1..322</a>

%F a(n) = DMYY_date('Mar 1 00' + A210889(n)).

%e The first palindromic date in D.M.YY format after 'Jan 01 00' is a(1)=10101 (= '10.1.01' = 'Jan 10 01' = 'Mar 01 00' + A210889(1) days);

%e The 10th palindromic date in D.M.YY format after 'Jan 01 00' is a(10)=101101 (= '10.11.01' = 'Nov 10 01' = 'Mar 01 00' + A210889(10) days);

%e The 44th palindromic date in D.M.YY format after 'Jan 01 00' is a(44)=2112 (= '2.1.12' = 'Jan 2 12' = 'Mar 01 00' + A210889(44) days);

%e The last (322nd) palindromic date in D.M.YY format after 'Jan 01 00' is a(322)=9999 (= '9.9.99' = 'Sep 09 99' = 'Mar 01 00' + A210889(322) days).

%Y Cf. A210883-A210889, A210891-A210895, A106605, A107273, A107275.

%K nonn,base

%O 1,1

%A _Hieronymus Fischer_, Apr 01 2012

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Last modified November 17 10:59 EST 2019. Contains 329225 sequences. (Running on oeis4.)